Party-line telephone system.



A. MARCHAND.

`PARTY LINE TELEPHONE SYSTEM. APPLICATION FILED MAR. 3', 1909.

1,013,412'. Patented @11.21912 4 SHEETS-'SHEET 1 A27? A. MARCHAND.

PARTY LINE TELEPHONE SYSTEM.

APPLICATION FILED MAR. 3, 1909.

1,01 3,412., Patented Jan. 2, 1912.

4 SHEETS-SHEET 2` @Kliff/memes: 27h/M314 uevlo A. MARCHAND. "PARTY LINE TELEPHONE SYSTEM.

APPLICATION FILED MAR. 3. 1909.

Patented Jan. 2, 1912.

4 SHEETS-SHEET 3 vil'xlcsscsz A. MARCHAND. PARTYv LINE TELEPHONE SYSTEM.

APPLICATION FILED MAR. 3. 1909.

Patented J an. 2. 1912.

4SHEETS SHEET 4 mir ic..

ALEXIS MARCHAND, F BRIDGEPORT, WASHINGTON.

PARTY-LINE TELEPHONE SYSTEM.

integra.

To all whom it may concern:

Be it known that I, ALEXIS MARCHAND, a citizen of the United States, and a resident `of Bridgeport, in the county of Douglas and particularly to the so-called party-line systems in which a plurality of stations are intercommunicating with or without connection to a central station.

It has for its object to enable lany desired station to be automatically selected from, and be connected to any other station of the system; and, at the same time, to automatically give suitable indications that the line is in use, or busy, and to effectively lock out said remaining stations s o that the communicating parties cannot be disturbed. nor the communications received by any of the other stations.

It has for its further object to automatically restore the various stations upon the conclusion of the connection, and to provide a suitable alarm in case such restoration is forgotten.

The various mechanism, and the connections to accomplish these objects are set forth in the following specification and shown in the accompanying drawings, in which- Figure 1 is a front elevation of a telephone box with the apparatus attached, portions of the various boxes being removed to permit a view of the mechanism. Fig. 2 is a. side elevation of a telephone box with the covers removed from the attached apparatus. Fig. 2a is a fragmentary end view of a switch. Fig. 3 is a partial side view and Fig. 4 a partial rear view of a movable rack; Fig. 5 is a plan view of the telephone box and attached apparatus, with the covers removed. Fig. 6 is a detail view of a spring. Figs. 7 to 9 are detail views of a stroke limiting device. Fig. 10 is a detail view of a system of operating levers and switches. Fig. 11 is a diagrammatic view illustrating the various electrical connections, and a number of stations under operating conditions.

Similar characters of reference designate Specification of Letters Patent.

Patented dan. 2, 11912.

Application led March 3, 1909. Serial No. 481,086.

corresponding parts throughout the several views.

Referring now to the drawings, 10 designates a telephone box located at each station, and is provided with a pulsating magneto bell 11, magneto 1Q, transmitter 13, receiver 13. and receiver hook 14. To the top .of box 10v is attached a box 15 containing the selecting mechanism hereinafter described, while to the side of box 10 is attached a box 16 containing the calling, annunciating, locking and restoring mecha-v nisms. The crank shaft 17 of handle 18 of the magneto 12 extends through this box 16 and is provided with a cam 19 engaging a pivoted, spring pressed arm 20 carrying a spring pressed pawl 21. Pawl Q1 engages and is adapted to raise a rack Q2, vertically movable in said box. and provided on itsv face with two sets of V-shaped teeth 23 .and 2l. The rack may be moved manually, when not locked. by means of a finger piece 25 extending through the box 16. and carries a pointer Q6 moving over a scale 27 on the side of said box. Upon the scale are marked the numbers of the various stations of the system. and to which the point-er must be set in calling any desired station, as will hereinafter be set forth. Two pointed blocks 28 and 29 are adapted to cooperate respectively with the said teeth 23 and 24, the block 29 being at a distance of one-half a toot-h above the block Q3. corresponding to one step of the rack so that when block 28 is in a notch, block Q9 is resting upon a crown, and vice versa. T he blocks 28 and 29 are carried respectively by vertical conducting strips 30 and 31 connected to the terminals of magneto 12. Suitable Contact points are carried by the strips 30. 31 and are arranged to engage either of the pairs of' conducting strips 33 and As the handle 1S is turned, the spring pressed arm Q0 rocks through the action of cani 19 and the pawl 21 will raise the rack 22 and thereby cause the blocks Q8 and 29 to alternately rest in a notch or upon a crown of the two sets of teeth Q3 and Q4, and thus alternately make contact with the strips 33 and 34, acting as a pole changing device to deliver electrical impulses of alternate'polarity at the terminals 35 and 36, corresponding to the number of teeth, of the rack Q2, advanced. Near the bottom of the rack 2Q, at 37, the teeth of set '24 arecut away entirely. At 38 of its set 23, there is a filled. portion to a height of one-half a tooth. The two succeeding and final teeth are also filled to the same height v as well as the remaining portion 39 of the rack 22. yThe position 38 corresponds to the stopped position of the rack 22 as will l hereinafter be set forth. In turning the handle '18, the said rack is not advanced in this position and the strips 33 and 34 will deliver a pulsating current of constant and the same polarity as the last impulse delivered to the selectingdevice; and this pulsatingl current A of constant polarity is usedto call by ring- 30 free, and is the normal position so that the current is broken and the magneto 12 can send no current into the line 100. The

pulsations of alternate polarity and the two successive fones of the same polarity are received by the selecting mechanism inx` the box 15 which is bridged across the line 100 at all of the stations, so that each selecting device will respond when the pulsations are generated by any station. These selecting mechanisms are arranged to control two switches 40 and 41, normally open. The former is closed immediately upon the selecting mechanism receiving an impulse, to close a local'circuit containing an indicating 'device 'and lock out mechanism. The switch 41 is normally open; andis closed, only in the desired station, upon the corresponding selecting mechanism receiving a predetermined number of alternate impulses, although the corresponding switches of the other selecting mechanisms may have been momentarily closed during the selection.

The selecting mechanism consists of an electro-magnet 42 bridged across the line 100 and provided with' a pivoted, magnetized armature 43, which will be attracted to the opposite poles of the electro-magnet according to the polarity of the current fre-l ceived, and thereby rock the said armature.

A rod 44 is iXedly attached to the armature" 43 and passes through a stroke limiting device, hereinafter described, and attached to the magnet side of frame plate 45. This rod passes through a slot 45 in the said frame plate 45 and is vibrated by the rocking of armature 43. Its outer end engagesa fork 46 of arm 47 of a lever 48, pivotally connected to the frame plate 45. This lever carries an advancing pawl 49 engaging the teeth of a vertically movable rack 50, slidably mounted on said frame plate. The lower end of the rack 50 is adapted to drop upon the lower member of switch 40 to nor# mally maintain the said switch open (see Fig. 2t). 'As soon as the rack 50 begins to ascend, however, switch 40 closes and re-v mains closed until the rack has returned to normal position. The vibration of rod 44 end of rack 50 is adapted to engage with one 4member of the switch 41 closing said 'switch` when .a predetermined number of impulses has advanced the rack 50 to the height for The upper' the particular station. In all'other stations the rack is likewise raised but may not reach the switch 41, or may move past sameand momentarily close t-he said switch 41 11i-passing, suficient teeth, only, being provided on the rack to allow same to advance'one ste beyond the contact point. .A locking paw 52 is provided to prevent return of the rack 50 until the line is restored. -When the two successive impulses of the same polarity are received by the electro-magnet .42; the limiting deviceabout to be describedpermits the fork 46 to bemoved a greater distance to the`right than before. Thls allows distance and it is moved voutwardly bycom- :ing in contact with a pin 49 and isvwith? '9o the pawl 49 to dropdownwardly agreater rnet side of frame plate 45, and through a j slot 56 therein passesthe rod .44 vibrated by the armature 43. Within the frame. vis a reciprocating Ymember 57. one of Whose ends is squared and the other beveled, the latter adapted to abut and slide upon a correspondingly beveled portion 58 of the frame and the former a shoulder 59. As the rod 44 is vibrated, the member 57 moves laterally with it, and in one direction rides upon the beveled portion 58 (Fig. 8) of 4the frame, and in the other strikes the shoulder 59 (Fig. 9) thereby limiting the vibration of the rod 44. A spring 60 engages rod 44 and is adapted to slightly move the member to the left as shown in dotted lines (Fig.l 9)' so that it will be freefof the shoulder 59; and the left hand portion being heavier, then drops about rod 44 to the dotted position shown and points above the shoulder so that if again moved in the same direction by rod 44 (toward the right), as in case the electromagnet 42 receives ay second impulse of the same polarity as the previous one, the member 57 will ride up on the' said shoulder to the position shown in Fig. 7, and thus allow the rod 44 a greater amplitude, (moving under spring 60 Fig. 6) limited by movement of the armature 43 and will thereby' release the pawls 49 and 52 as explained.

vThe switch 40 is in a local circuit including a local battery 61, switch 62 and an annunciator 63. The switch 62 is opened only in the callingstation in setting the pointer 26 as hereinafter described, Upon the closing of switch 40 the local circuit is closed and the annunciator will indicate by some suitable signal visible through an opening 64 that the line is busy. The switch, as stated, will remain closed, and thereby display the signal (except in calling station when receiver hook 14 is up) unt-il the rack 50 has been returned to its normal osition. A shunt circuit ,is added to the circuit of the annunciator 63, and excludes the switch 62 but includes a switch 65 operated by the receiver -hook 14 and normally closed.

A. local alarm circuit includes the battery 61, switch 65, a switch 66 normally open and closed only in the calling instrument when setting the pointer in calling, as hereinafter described, and a buzzer 67 or other suitable alarm. v

A shunt circuit is added -to the selector switch 41 and includes a switch 68 normally open and adapted to be closed at the calling, station only, and when setting the pointer 26 in calling, and throws the talking circuit 101 of the calling station into the line 100.

A cut-out switch 69 normallyrclosed is inserted in the bell circuit 102, which is bridged across the line 100 at each station but,beyond the switch 41, and is adapted to be opened at the calling station, only when setting the pointer 26, to cut out the bell 11.

The operation of the system is as follows The pointer 26 is first set to a number corresponding to the station it isdesired to communicate with, by grasping tinger piece 25 and moving same downwardly, the instrument in normal condition having the pointer at its extreme upper limit. At the beginning of the downward movement of the rack 22, a projection 71 of said rack encounters a. pin 72 ofarm 7 3 of a bell crank, forcing said pin slightly to the right (Fig. 10)v provided the arm 20 is in its lowest position under action of the cam 19. If thearm be not in its lowest' position the rack cannot be moved and the crank must be turned to place it so. This causes pin 72 to move pawl 21 out of engagement with the teeth of the rack and allows said rack to be set by moving the finger piece 25 downwardly. A spring washer 74 holds the said bell crank in this position until it is returned by'turning the handle 18 which moves the cam 19 tothe horizontal position shown in dotted lines and causing the arm 20 thereby to rise and through a pin 75 attached to its underside,to engage arm 76 of the bell vcrank and return same. The pawl crank 78. This latch acts as a stop for a shoulder 79 on the under side' of the rack 22 (Figs. 3 and 4) limiting its upward Inovement so long as the magnets of annunciator 63 are energized. The upward movement of rack 22 caused by turning the handle 18 has impressed upon the line 100 a succession of electrical impulses of alternate polarity as explained. This actuates the selecting devices 15 at the various stations, closing the 'switches 40 and thereby energizing the lnagnets of the annunciators 63 to display a suitable signal to indicate that the line is in use. At the same time it locks the rack 22 in all of the stations except the calling station which is not locked until, as explained, a predetermined number of turns has been given the handle 18) through latch 77 entering a notch 80 at the under side of the rack 22 (Figs. 3 and 4).' The rack cannot therefore be moved in any station but the calling station, and its upward movement in such station is also stopped, as explained. When the rack 22 at the calling station is thus stopped in its upward movement, furl ther turning of handle does not advance it, but impresses upon the line 100 a pulsating current of constant polarity and of the same polarity as the last impulse impressed. At the time of reaching this point, the predetermined number of impulses to close switch '41 of the desired station B will have been made, and the talking and transmitting circuit 101 aswell as the bell circuit 102 of said station will thus have been cut in the line 100. The pulsating current of constant polarity generated at the calling station A (Fig. 11) will cause the bell 11 of station B to ring and call same, the switches 41 of the remaining stations C having been only momentarily closed or not at all, the bells of said stations will not respond, nor will their talking and transmitting circuits 101 be cut inthe line 100. Upon lifting the/receiver hook 14 at the calling station A, the local annunciating circuit will be broken at switch 65. Switch 62, also,has been opened tion B as well as at the remaining stations C has no effect upon the local annunciating and locking circuit as the switch 62 in these stations has not been opened, and the circuit is closed through said switch and switch .opens same at the calling station only, due

to the movement of rack 22, so that the calling bell 11 of the calling station A does not ring when ringing the called station B. The normally open switch 66 in the local circuit is closed by the movement of a pin 82 of bell crank- 83 actuated by va pin 84 on the underside of rack 22. This engages a nose 85 on said bell crank when. the rack 22 has been brought into calling position. The normally open switch 68 sh'unted across selector switch 41 is adapted 'to be closed by the movement of pin 82. but not until the handle 18, is turned, so that it is impossible to cut in the talking and transmitting circuit 101 at the calling station A, without impressing an impulse or impulses upon the line 100. This is accomplished by means of a second bell crank 90 provided with a nose 91 adapted to be engaged by a pin 92 on the underside of thera-ck 22.' The inner arm 93 of said bell crank carries a pin 94 which slides between the contact springs of switch 68, and when the bell crank is-forced inwardly through the downward movement the pin 92,' presses the lower spring of said switch downwardly so that contact will not be made through switch 68 even if the upperpin 82 tends to close'same. A spring washer 95 holds said bell-crank in any position it is moved. An arm 96 extends down- Y wardly from the arm 93 into a groove-97 of a wheel 98 driven by the handle 18. This groove contains a'projection 99 which, when t-he cam 20 is in the horizontal position l shown in dotted lines engages. said arm 96 an'd returns the bell crank 90 "to normal position, permitting the switch 68 to b'e closed. To restore the various staticns to normal condition, the handle 18 must be given several turns, which will raise the rack 22 into its normal position, the rack having been unlocked after calling by the lifting of receiver 13 which opened the switch 65 and thereby the local circuit controlling the an' nunciator 63. The upward movement of the rack 22 has caused the block 29 to move over the portion 37 and the block 28 over the lilled portion 38 as well as the two final teeth of the rack. In this movement the twoisucceeding impulses of the same larity caused by the tfvo final teeth, have operated the various selecting devices as set forth to restoresame to normal condition. In the final and normal position of the rack 22, block 29 rests upon the removed portion 37 and block 28 upon the lilled portion 39 beyond the two iinal teeth, and the circuit will thereby be broken through the contact controlled by the block 28. Should the receiver 13 have been placed upon hook 14 before restoring, alarm would have been given by the buzzer 67 through closing of switch 65, as the switch 66 would still be closed. i

If one of the stations be made a'central station, the party line herein described may be connected vto otberdirect lines orsimilar party lines.

I claim 1. In a telephone system: a plurality of stations, Aand the usual connecting circuit across which the said stations are bridged, the talking circuits of said stations being normally disconnected from said connecting circuit; a selecting device bridged across said connecting circuit at each station and continually connected thereto; and a calling device to automatically connect any two of said stations, bridged across said connecting circuit at each station but normally discon-- fvice to automatically connect any two of Said stations, bridged across said connecting circuit at each station but normally disconnected therefrom; and means to automatically lock out the remaining stations.

3. In a telephone system: a plurality of stations, and the usual connecting .circuit across which the said stations are bridged, the talking circuits of said stations being normally disconnected from said connecting circuit; a selecting device bridged across said connecting circuit at each station and continually connected thereto; a calling device. to automatically connect any two of said stations, bridged across said connecting circuit at each station but normally disconnected therefrom; means to automatically lockout the remaining stations; and means to automatically indicate at each station the condition of said station.

4. In a telephone system: a plurality of stations, and the usual connecting circuit across which the said stations are bridged, the talking circuits ofsaid stations being normally disconnected from said' connecting circuit; a selecting device bridged across said connecting circuit at each station and continually connected thereto; a calling device to automatically connect any two of `"said sections, bridgedvacross said connecting circuiti at each station but .normally disconnected therefrom; and means to automatically restore all of the stations to normal condition.

5. In a telephone system: aplurality ofstations, and the usual connecting circuit Y normally disconnected from said connecting circuit; a selecting device bridgedv across said connecting circuit at each station and continually connected thereto; a calling de vice to automatically connect any two of said stations, bridged across said connecting circuit at each station but normally disconnected therefrom; means toautomatically lock out the remaining stations; and means to automatically restore all of the stations to normal condition.

6. In a telephone system: a plurality of stations, and the usual connecting circuit across which the said stations are bridged, the talking circuits of said stations being normally disconnectedvfrom said connecting circuit; a selecting device bridged across said connecting circuit at each station and continually connected thereto; a calling de- 'vice to automatically connect any two of said stations, bridged across said connecting circuit at each station but normally disconnected therefrom; means to automatically lock out the remaining stations; means to automatically indicate at each station the conditions of said station; and means to automatically restore all of the stations to normal condition.

'2'. ln a telephone system: a plurality of stations, and the usual connecting circuit across which the said stations are bridged, the talking circuits of said stations being normally disconnected from said connecting circuit; a selecting device bridged across said connecting circuit at each station and continually connected thereto; a calling device to automatically connect any two of said stations, bridged across said connecting circuit at each station but normally disconnected therefrom; means to automatically lock out the remaining stations; means to automatically indicate at each station the condition of said station; and means to automatically restore from the calling station all of the stations to normal condition.

8. ln a telephone system: a plurality of stations, and the usual connecting circuit across which the said stations are bridged, the talking circuits of 'said stations being normally disconnected from said connecting circuit; a selecting device bridged across said connecting circuit at each station and 'continually connected thereto; a calling device to automatically connect any two ot said stations, bridged across said connecting circuit at each station but normally disconnected therefrom; means to automatically restore all the stations to normal condition; and means to automatically give an alarm in case the calling receiver is hung up while the stations are not restored upon concluding the connection.

9. ln a telephone system: a plurality of stations, and the usual connecting circuit across which the said stations are bridged,

the talking circuits of said stations being normally disconnected from said connecting circuit; a selecting device bridged across said connecting circuit at each station and continually connected thereto; a calling device to automatically connect any two of said stations, bridged across said connecting circuit at each station but normally disconnected therefrom; means to automatically lock out the remaining stations while the two stations are connected; means to automatically indicate at each station the condition of said station; means to automatically restore all of the stations to normal condition; and means to automatically give an alarm in case the calling receiver is hung up while the stations are not restored upon concluding the connection.

l0. In a telephone system: aplurality of stations, and a connecting circuit across which the said stations are bridged, the talking circuits of said stations being normally -disconnected from said connecting circuit; means at each station and normally disconnected from the connecting circuit to impress upon' the said connecting circuit elec- 'trical impulses or" alternate polarity; and a selecting device bridged across said circuit at Leach station, continually connected there-v to-and responsive to the said electrical impulses ot alternate polarity, v

11. In an electrical system: a plurality of stations, and a connecting circuit across which said stations are bridged; means to limpress upon said connecting circuita succession of electrical impulses of alternate polarity, a pulsating current of constant and the same polarity as that of the .last impulse of said succession of impulses, and two successiveimpulses of same polarity but ot opposite polarity to the last of said succession of impulses; and a selecting device bridged across the connecting circuit at each station and responsive to the succession of impulses of alternate polarity, and the two said impulses of same polarity, but not to the pulsating current of constant polarity.

12. ln an electrical system: a plurality of stations, and a connecting circuit across which said stations are bridged; means at each station to impress upon the said connecting circuit a succession of electrical impulses of alternate polarity, a pulsating current of constant and the same polarity as that of the last impulse of said succession of impulses, and two successive impulses of same polarity but of opposite polarity to the last of said succession of impulses; and a selecting device bridged across the circuit at each station and responsive to the impulses of alternate polarity; a contact device advanced in a step by step movement by said selecting device, and not advanced when the selecting device receives the pulsating current of constant polarity, and returned to normal position when the selecting device receives the two successive impulses of the same polarity.

13. In an electrical system: a plurality of stations, and a connecting circu-it across ,which said stations are bridged; means at each station to impress upon the said connecting ciicuit a predetermined number of electrical impulses of alternate polarity and two successive impulses of the same polarity; a selecting device bridged across the connecting circuit at each station.; a contact device operated by said selecting device; two switches controlled by said contact device one to be closed upon thel selecting device receiving one or more impulses, and the other upon the selecting device receiving a pre-l determined number of the electrical impulses of alternate polarity.

14. In an electrical system: a plurality of stations, and a connecting circuit across which'said stations are bridged; means at eachstation to impress upon the said con? necting circuit a predetermined number of electrical impulses ofalternate polarity and two successive impulses of the same polarity; a selecting device bridged across the connecting circuit at each station; a contact device operated by said selecting device; two switches controlled by said contact deviceone to be closed upon the selecting device receiving one or more impulses, and the other upon the selecting device receiving a predetermined number of electrical impulsesof alternate polarity; and means to return said contact device to normal position upon the selecting device receiving the two successive impulses of the same polarity.

15. The combination with a party line telephone system 'comprising a plurality of stations whose talking and transmitting circuit is normally cut out, and a calling device and selecting device at each station, of means to actuate the selecting devices from any of said stations, a switch at each stat-ion controlled by the corresponding selecting device and Anormally cutting out said talking and transmitting circuit and adapted to be automatically closed from any of the calling devices, and a second normally open switch at each station controlled by the corresponding selecting device,l a local circuit controlled by said latter switch, an annunciating device included in said local circuit, and mechanism to lock the calling device and controlled by said annunciating device.

v16. The combination with. a party line telephone system comprising a plurality of stations whose talking and transmitting ycircuit is normally cut out, of a selecting device, and a callingA device at each station to actuate the said selecting devices, a switch at each station controlled by the corresponding selecting device and normally cutting out said talking and transmitting circuit and yadapted to be automatically closed from any of said calling devices, a second, normally open switch at each station controlled by the corresponding selecting device, a, lo cal circuit controlled by said lat-ter switch,

an annunciating device included in said lo` telephone system comprising a plurality of stations whose talking and transmitting circuit is normally cut out, of a selecting device, and a calling device at each station to actuate the said selecting device, a switch at each station controlled by the corresponding selecting device and normally cutting out said talking and transmitting circuit and adapted to be automatically closed from any` of said calling devices, a second, normally open switch at each station controlled by the correspondingselecting device, a local circuit controlled by said latter switch, an annunciating device included in said local circuit, lockout mechanism controlled by said .anniinciating device, a normally closed switch' in said local circuitoperated by the calling device of the corresponding station, a shunt across the local circuit excluding said normally closed switch, and a normallyA closed switch included in said shunt and controlled by the telephone receiver hook.

18. The combination with a party line telephone system comprising a plurality of stations whose talkingand transmitting circuit is normally cut out, of a. selecting device,andv a calling device at each station to actuate the said selecting devices, a switch at each station controlled by the corresponding selecting device and normally cut-ting out said talking and transmitting circuit and adapted to be automatically closed from any of said calling devices,a second, normally open switch at each station controlled by the corresponding selecting device, a local circuit controlled by said latter switch, an annunciating device included in said local circuit, lockout mechanism 'controlled by said annunciating device, a normally closed switch operated by the calling device of the corresponding station, ashunt across the lo cal circuit excluding said normally closed cuit/is normally cut out, of a selecting device at each station, and a calling device at each station to act-nate the said selecting devices, aswitch at each station controlled by the corresponding selecting device and nor mally cutting out said talking and transinitting circuit and adapted to be automatically closed from any ot said calling devices, a shunt across said switch, a normally open switch included in said shunt and operated by the said calling device, a second, normally open switch at each station controlled by the corresponding selecting device, a local circuit controlled by said latter switch, an annunciating device included in said local circuit, lockout mechanism controlled by said annunciating device, a normally closed switch operated by the calling device of the corresponding station, and a shunt across the local circuit excluding said normally closed switch, a normally closed switch included in said shunt and controlled by the telephone :receiver hook,` a second local circuit, an alarm device included in said second local circuit, a switch normally open and controlled by the calling device, and a normally closed switch controlled by the telephone receiver hook.

20. The combination with a arty line telephone system comprising a p urality .ol

vstations Whose talking and transmitting circuit is normally cut out, of a selecting device at each station, and a calling device at each station to actuate saidselecting devices, a switch at each station controlled by the corresponding selecting device and normally ycutting out said talking and transmitting circuit and adapted to be automatically closed from any of said calling devices, a shunt across said switch, a normally open switch included in said shunt and operated by the said calling device, a calling bell bridged across said talking and transmitting circuit, a normally closed switch controlling said calling bell and operated by said calling device, a second,vnor mally open switch at each station controlled by thev corresponding selecting device, a local circuit controlled by said latter switch, an annunciating deviceincluded in saidlocal circuit, lockout mechanism controlled by said annunciatin'g device, a normally closed switch operated by the calling device of the corresponding station, a shunt across the local circuit excluding said normally closed switch, a normally closed switch included in said shunt and controlled by the telephone receiver hook; and a second localcircuit, and an alarm device, a normally open switch controlled by the calling device, and the said normally closed switch controlled by the telephone receiver hook, included in said second local circuit.

` 21. ln a system ot the 'character set forth,

a selecting device comprising an `electromagnet; a pivoted armature; a rod carried by said armature and adapted to be vibrated upon the electro-magnet receiving electrical impulses of alternate polarity; an arm adapted to be rotked by said rod; a movable rack; a pawl actuated by said rocking arm to advance said rack; a locking pawl to prevent return of said rack; and means to .limit the amplitude of vibration of said rod upon the said electro-magnet receiving two successive impulses of the same polarity. y 22. 'ln a system of the character set forth, a selecting device comprising: an electromagnet; a pivoted armature; a rod carried by said armature adapted to be vibrated upon the electro-magnetreceiving electrical impulses of alternate polarity; an arm adapted to be rocked by said rod; a vertically movable rack; a pawl actuated. by said rocking arm to advance said rack; a locking paWl to prevent return of said rack; means to limit the amplitude of vibration ot' said rod, and comprising a frame; a reciprocating member held therein, having one end squared and the other beveled and provided with a slot through which the said rod passes; a bevel stop of said trame and a squared shoulder with which the said beveled and square ends of the said reciprocating member are respectively adapted to cooperate; and a spring adapted to exert pressure against the sald rod.

23. ln a'system of the character set forth,

vacalling device comprising: a movable rack; means to manually set same; means to automatically lock said rack in normal position; means to advance same in a step by step movement to calling position; and means to automatically lock same in calling position. f. f

24. In a system of the character set forth, a calling device comprising: a movable rack; means to manually set same; means to automatically lock said rack in normal position; a pawl to advance said rack to calling position in a step. by step movement; means to Arelease said pawl to permit said rack to be manually set; and means to automatically lock said rack in calling position.

25. ln a system of, the character set forth, a calling device comprising: a movable rack; means tQmanually set same; means to advance same in a step by step movement to calling position; means to automatically lock same in calling position; and a normally closed switch 1n circuit with said locking means and means to open said switch to unlock said rack.

126. In a system of the character set forth,

.calling means to lproduce a succession of electrical impulses ot alternate polarity comprising: a movable rack; means to advance said rack in a step by-step movement;

-two rows of teeth on said rack; and contact meansvcoperating with the said rows of teeth to alternately close"anlelectric.cir-V comprising: a movable rack; means to advance said rack in a step by step movement;

two rows of teeth on said rack; two blocksl mounted respectively upon'two flexible conducting lstrips and coperating with said rows of teeth, the one block a distance of one-half a tooth inadvance of the other; two conducting strips at opposite sides of each of said flexible conductlng strips; and contact points 4carried by said flexible conducting strips adapted to alternately make contact with' the respect-ive conducting strips located at opposite sides of same.

28. In a system of the character setjorth, means to produce a succession of electrical impulsesof alternate polarity, a pulsating current of constant polarity and' two suci cessive pulsations of the same polarity, but of opposite polarity to the last of said' succession of impulses, comprising: a movable rack; means to advance said rack in a step by step movement; two rows of teeth on said rack a portion of oneset being removed, and at the corresponding position. of the 'other a portion filled to approximately onevhalf the y'depth of a tooth and including two successiveteeth and then a portion free of teeth; two blocks mounted upon flexible conductingstrips,zone a distance of onehalf a tooth in advance of the other, said blocks coperating with said rows of teeth; two conducting strips at opposite sides of each of said ,llexibleconducting strips; and contact points carried-by said flexible ccnducting strips adapted to make contact with the respective conducting st'rips located at opposite sides of same.

Signed at New York in the county f New Yorkl and Stateof New York this 1st day of'Mareh A. 1909.v

. ALEXIS MARCHAND.

Witnesses:

LAURA E. SMITH, FREDK. F. 

